God, Then Seapower: The Religious Life of Mahan

January 5, 2016

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Suzanne Geissler, God and Sea Power: The Influence of Religion on Alfred Thayer Mahan (Naval Institute Press, 2015)

The cardinal sin of the book reviewer is to review the book you wanted to read, rather than the book you read. With malice aforethought, I now plunge headlong into such sin.

Suzanne Geissler’s God and Sea Power is a delightful, well-researched, and fascinating book; a work that should be added to the canon about America’s Apostle of Seapower, Alfred Thayer Mahan. It is deeply biographical, concerning itself primarily with the man’s Christian life, albeit a Christian life lived through a sea-going career and later a life of academic and contemplative work. For those thirsting for a more complete picture of Mahan as a man, look no further.

Until I started reading this book, my interest in Mahan was never in his spiritual life or his place in humanity. I admit to little or no interest in how he was raised or in how he raised his own children. His struggles with his Maker and his influence within his church (the Episcopal) have never risen to a level of great import. No, my interest in Mahan springs solely from his roles as historian and strategist, and the impact he had on the world around him. I accepted this review assignment based only on reading the title, which led me to believe that the book addressed how Mahan’s spiritual life impacted his works on strategy and history. This hope was in large measure reinforced in Geissler’s introduction, in which she reveals her aim:

The present work is the first full-length study of Mahan’s religious faith. It focuses on three issues: (1) what was the content of Mahan’s religious faith and how did it develop, (2) how did it influence his naval and geopolitical thinking, and (3) what role did Mahan play within the Episcopal Church.

Geissler is wildly successful in addressing the first and third issues, but does not succeed in demonstrating a tangible link between his faith and his work. So while the book adds great value to knowledge of Mahan the individual, it offers little additional insight into Mahan the navalist.

Mahan’s early life was primarily influenced by two men — his father Dennis Mahan and his uncle Reverend Milo Mahan. Dennis was a legendary professor at West Point, and most of the great Civil War generals were his students. In one particularly interesting vignette, Alfred, then in his twenties, met General Sherman during the Civil War as Sherman completed his march to the sea at Savannah. At the meeting, Mahan presented Sherman with a letter from Dennis praising Sherman, which caused Sherman to smile as he had in younger days, as when “…dismissed from the blackboard with the commendation ‘Very well done, Mr. Sherman.’” Dennis raised Alfred and his siblings in what appears to have been a typical mid-19th-century Protestant household, one in which faith was central, mediated by a “High Church” brand of Episcopalian religious education. As a lay leader in the modern Episcopal Church, Geissler is particularly adept at distinguishing among the various strains of thought within the faith in the 19th century, and she is convincing that both Dennis and Alfred adhered to a mainline, establishment version of the religion.

Dennis’s brother Milo was a churchman of some note in 19th-century America, and it was into Milo’s care that a teenaged Alfred was placed in order to see to his education. Milo also subscribed to “High Church” Episcopalism and his influence on Alfred’s spiritual development is well documented here. Alfred’s preparation at Milo’s knee must have been effective, as one of Mahan’s claims to naval fame is having “passed out” of his entire plebe year at Annapolis, something no one had done to that point in the school’s history. Apparently, Mahan studied the school’s entrance documents and saw a provision allowing for such promotion, something no other student had to that point noticed or attempted.

Geissler is at her best in this work in laying out a detailed and careful examination of Mahan’s development as a Christian. His thoughts on the rector at the Naval Academy (not a fan), his views on the Christianity of his shipmates (lacking), and especially his singular sense of unworthiness to receive God’s grace, provided me with a far more complete picture of Mahan during his formative years at Annapolis and in the fleet (1856–1871). What I also found interesting was that putting aside his academic success at the Naval Academy (second in his class), there was virtually nothing in either his interests or his performance as a naval officer that would lead one to believe that he would eventually change the world’s understanding of the nature of the relationship between seapower and national power.

In fact, to the extent that Mahan was thinking about anything in these formative years, it was about religion and faith. Mahan’s letters and diaries from the period reveal a man who was wrestling with his own conscience, trying to reconcile his absolute belief in the redeeming grace of God with his own unworthiness to receive it. By 1871, this process had largely worked itself out, with Geissler pointing to what Mahan later described as something of a conversion experience occurring that year, after which we see very little of this spiritual contention for the rest of his life (he died in 1914 at the age of 74). It occurred to me in reading this work that in order for the strategist and historian to emerge, the spiritual battle raging inside Mahan’s mind and heart must be won. Once Mahan had worked out his faith struggle, there appeared something of a clarity of mind that led in short order to marriage, fatherhood, and greatness.

I came away from this work with a much more coherent understanding of Mahan as a complete individual than I had before reading it. Geissler’s intricate understanding of 19th-century American religion and her thorough account of Mahan’s post-Navy influence on American Episcopal thought fill in some of the blanks that exist in a more holistic understanding of this great figure in American history. For those in search of a well-written, well-researched, and interesting biographical work on Mahan, one that provides vivid glimpses into many aspects of 19th-century American life (family, church, community, intellect), you can do no better than this excellent book. Those seeking an explicit tie between Mahan’s faith and his genius for seapower must look elsewhere.


Bryan McGrath is the Managing Director of The FerryBridge Group, LLC, and the Assistant Director of Hudson Institute’s Center for American Seapower.


Photo credit: Alessandro Caproni (adapted by WOTR)

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3 thoughts on “God, Then Seapower: The Religious Life of Mahan

  1. One cannot avoid Mahan’s spiritual aspects after even spending just a little time in his published correspondence as edited by Robert Seegar and Doris McGuire. That said, it seems clear to me that Bryan has identified a clear area for further research on item number 2. My own position is that Mahan’s spiritual influenced his geostrategic views as follows: he believed in Divine Providence, thus he felt himself, the US, and history, all at God’s disposal to do His will. It is really that simple. I leave the extrapolations to American (or British) exceptionalism to others.
    Dr. John T. Kuehn, Fort Leavenworth, KS Commander USN (retired)

  2. Unless Mahan was born into a theocracy I doubt that you would find much of an obvious link, at least to the secular of the world, between his faith and his strategy. Most contemporary Christian soldiers, seamen included, do not preface their tactical and strategic thinking with phrases like it, “in accordance with God’s will” or ,”if God is willing.” Another religion does that.

    Christian Faith is not religion, it is a shaping spiritual aspect of the believer’s life that affects every aspect of their being. I work out not because the Army tells me too but because God blessed me with a healthy body and I am to take care of it, but I don’t walk around tell other soldiers, “Yep, I am off to PT so that I can be a Godly Christian steward.”

    Th world has very confused ideas about how devout Christians operate. But the curious might find some better understanding of how Christian fighters think be reading Aquinas, Lewis, Neibuhr, among others. Couple that with a generally founded love for Western freedoms and Western civilization’s essential philosophies about the value of the individual and you will being to see more connects between professing Christians and the strategies that they advocate.


    1. You would be surprised. I have met many pretentious Christians, some in the military. Not just Jehovah witness types either, I’m talking like Covenant, Sword, Arm of the Lord kind of stuff. Some Identity Christians. I have yet to find a faith, or lack of one, that doesn’t produce people who try to shove it down the heathen throats of others.